function logout() {
	jQuery.ajax({
		type : "POST",
		url : "php/service_logout.php",
		data : {
			logout : true
		},
		dataType : "json",
		beforeSend : function(xhr) {
		},
		success : function(result) {
			if (result.success == true) {
			window.location.reload();
			} else {
			alert(result.message);
			}
		},
		error : function(e) {
			alert("Lỗi kết nối");
			result = false;
		}
	});
}